Evaporator



June 2, 1936.

C. H. STEENSTRUP EVAPORATOR Filed Aug. 28, 1935 Inventor: (/f /il. A! Jrfz'wsmyp y 'ivwz f mflw Hi Attorney.

Patented June 2, 1936 PATENT OFFICE EVAPORATOR Carl H. Steenstrup, Niskayuna, N. Y., assignor to General Electric Company, a corporation of New York Application August 28, 1935, Serial No. 38,204 6 Claims. (01. 62-126) My invention relates to flooded evaporators for refrigerating machines of the type employing a liquefiable refrigerant and a liquid lubricant.

During the operation of refrigerating machines which employ refrigerants such as sulphur-dioxide and a liquid lubricant, such as a refined mineral oil, there is a tendency for the oil to be carried through ,the system and into the evaporator. The lubricant may be separated from the refrigerant by gravity, but because of the boiling and agitation of the liquid refrigerant this separation cannot be accomplished readily in the header unless a quiet zone of liquid is provided. It is, therefore, necessary to provide some arrangement for separating and collecting the lubricant in the evaporator and for returning it to the compressor for use in lubricating the working parts of the mechanism in order not to deplete the supply of lubricant available for lubricating 2 the working parts of the mechanism.

Accordingly, it is an object of my invention to provide a flooded evaporator for refrigerating machines of the type employing a liquefiable refrlgerant and a liquid lubricant having an imof lubricant, from the evaporator.

Further objects and advantages of my invention will become apparent as the following description proceeds and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention reference may be had to the accompanyingdrawing, in which Fig. l-is a-front elevation view of a household refrigerating machine provided with an evaporator embodying my invention; Fig. 2 is an enlarged perspective view partly in section of the evaporator of the refrigerating machine shown in Fig. 1; Fig. 3 is an enlarged fragmentary view'partly in section of a portion of the evaporator shown in Fig. 2'; and Fig. 4 is a sectional view of the evaporator on the line 4-4 of Fig. 3. Referring now to the drawing, in Fig. 1 I have shown a refrigerating machine comprising a casing ill containing a motor and a compressor, an air-cooled condenser ll, a receiver or float valve chamber 12, and an evaporator l3 arranged to cool a compartment M of a household refrigerator cabinet l5. During the operation of the refrigerating machine shown gaseous refrigerant is compressed by operation of the compressor of the casing l0 and is discharged into the condenser I l where it is cooled by absorption of heat from the surrounding air and is liquefied. The liquid proved arrangement for facilitating the removal refrigerant flows from the condenser H into the receiver l2, and when a predetermined amount of liquid has-collected in the receiver a float therein rises and liquid refrigerant is admitted through a liquid line Hi to the evaporator 5 H3. The liquid refrigerant within the evaporator i3 is vaporized by the absorption of heat from the compartment It and the vaporized refrigerant separates from the liquid in headers I1 and E8 of the evaporator and is withdrawn therefrom 10 through a suction conduit is and is returned to the compressor. This cycle of operation continues as long as the compressor within the oasing Hi is operating. The compressor is controlled thermostatically in the usual manner in response 15 to the temperature of the evaporator or of the air within the compartment M.

In order to lubricate the compressor a quantity of liquid lubricant such as mineral oil is provided in the bottom of the casing in. This lubri- 20 cant is supplied to the working parts of the motor and compressor by operation of a suitable pump driven by the compressor motor. As a result of the distribution of oil to the working parts of the compressor some of the oil in the form of a mist flows with the compressed refrigerant into the condenser and thence to the evaporator l3. The oil and liquid refrigerant in,the evaporator are intimately mixed, but tend to separate by gravity the oil floating ontop of the refrigerant. The separation is, however, hindered by the agitation of the liquid due to the boiling of the refrigerant and is therefore inefficient. In order to prevent depletion of the supply of oil for lubricating the working mechanism it is necessary to separate efficiently the oil and liquid refriger ant and to return to the casing in the oil collected on the surface of the liquid refrigerant in the evaporator i3.

In accordance with my invention, I provide a bafiie within one of the headers of the evaporator so arranged as to provide an elongated chamber within the evaporator partially below the level of liquid to maintain a quiet zone of liquid within the header, so that the lubricant and liquid refrigerant can readily separate by gravity, and I connect the suction conduit to communicate with the chamber in order to withdraw lubricant collected on the surface of .the liquid refrigerant within the baflie. I also con- 50 struct the evaporator so that the circulating paths thereof provide a relatively quiet zone of liquid refrigerant near the open end of the baffle. 7

Referring now to Fig. 2, evaporator I3 is of U-shaped form having legs 20 and 2| providing side walls of a freezing compartment and having theheaders l1 and I8 respectively formed in the upper portions thereof, a plurality of conduits or passages 22' are provided in .the walls of the evaporator and connect the headers, each of the passages communicating at one end with the header l1 and at the other end with the header I8. A manifold 23 is formed in the wall 20 near the lower portion thereof and connects a plurality of the passages 22. A vapor conduit 25 connecting the headers I! and I8 above the level of liquid refrigerant therein is provided to equalize the pressures in the headers and to remove gaseous refrigerant from the header IT. The liquid line l6 enters the manifold 23 and terminates in a tube 26 closed at theend and provided with orifices 2'! connecting alternate ones of the passages 22 and arranged to inject refrigerant upwardly into those passages. During the operation of the refrigerating machine liquid refrigerant enters the tube 26 and flows upwardly in the alternate passages as indicated by dotted arrows. During the normal operation of the refrigerating machine the headers l1 Atchison and is described and claimed in his co-pending application Serial No. 750,977 filed November 1, 1934 and assigned to the General Electric Company assignee of this present application. I do not therefore herein claim anything claimed in the said Atchison application which is to be regarded as prior art with respect to this present application, my invention relating to an improved arrangement for separating and removing lubricant from the header of an evaporator.

The continuous circulation of refrigerant and the absorption of heat from the compartment l4 produces a violent bubbling or boiling action in the headers l! and I8 and it is necessary to provide some arrangement forkeeping the liquid refrigerant from splashing into the suction line l9. Furthermore, the violent agitation of the liquid makes it dimcult for the lubricant and liquid refrigerant to separate by gravity and for the lubricant to collect in such a manner that I it may be removed from the evaporator without also removing liquid refrigerant In order to provide a" quiet zone of liquid within the header l8 for the gravity separation of lubricant and liquid refrigerant I secure a,substantially cylindrical bafiie 28 within the header and arrange the suction line IS in communication with the interior thereof. The arrangement of this baflle is clearly shown in Figs. 3 and 4. One end 29 of the baflle is closed, and it is to this end that the suction line I9 is connected in communication with the interior of the bailie, the bailie being supported within the header by the suction line and by the side wall of the header to which the baffle is secured by spot welding orin some other suitable manner. The other end of the baiile 28 is open,

and since'the baiile is arranged horizontally within the header and is partiallybelow the level of liquid refrigerant, a quantity of liquid refrigerant will cover the lower portion of the interior of the baffle. A quantity of liquid lubricant 30 separates by gravity from the liquid refrigerant and collects on the surface of the liquid refrigerant as indicated at 3|, and due to the violent agitation of the liquid in the header I 8 there is a tendency for the oil to accumulate in a greater quantity on the quiet surface near the closed end 29 of the baille 28. The suction line t9 communicates with the header 18. within the baiile 28 near the closed end thereof, and during operation-of v the compressor the oil which collects on the surface of the liquid refrigerant is drawn into the suction line and returned to the compressor. The

omn end of the baffle is preferably arranged,

above one of the passages 22 in which there is a downward flow of liquid refrigerant from the header l8 since the liquid above the'downward passage will be more quiet thanthat above the itating the separation of lubricant from liquid refrigerant ,and the removal of lubricant from the surface of the liquid refrigerant in the header.

and at the same time provides a quiet zone of liquid preventing the splashing of liquid refrigerant into the suction line and possible damage to .the compressor mechanism.

While I have shown and described a particular embodiment of my invention 'in connection with an evaporator for a household refrigerating machine, modiflcations will occur to those skilled in.

the art. I do not, therefore, desire my invention to be limited to the construction shown and described, and I intend in the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. A flooded evaporator for refrigerating machines of the type employing a liqueflable refrigerant and a liquid lubricant separable by gravity and including a header for separating liquid and gaseous refrigerant, means including a suction conduit entering said header for removing gaseous refrigerant and lubricant therefrom, and means including an elongated vessel in said header communicating at one end with said conduit and open at the other end and having the interior thereof throughout its length partially below the level of and covered by the liquid refrigerant in said header for separating lubricant from the liquid refrigerant in said evaporator.

2. A flooded evaporator for refrigerating machines of the type employing a liqueflable refrigerant and a liquid lubricant separable by gravity and including aheader for separating liquid and gaseous refrigerant, means including a suction conduit entering said header for removing gaseous refrigerant and lubricant therefrom,-

- ranged horizontally within said header and extending throughout its length partially belowthe level of liquid refrigerant in said header for. separating lubricant from the liquid refrigerant municating with said header within said baffle.

3. A flooded evaporator for refrigerating machines of the type employing a liquefiable refrigerant and a liquid lubricant separable by gravity and including a header for separating liquid and gaseous refrigerant, means-including a suction conduit entering said header for removing gaseous refrigerant and lubricant therefrom, a substantially cylindrical bafile closedat one end and open at the other end and arranged horizontally within said header, said bafile extending throughout its length partially below the level of liquid refrigerant in said header, said suction conduit being connected to the closed end of said bafiie and communicating with the interior thereof.

4. A flooded evaporator for refrigerating machines of the type employing a liquefiable refrigerant and a liquid lubricant separable by gravity and including a header for separating liquid and gaseous refrigerant, means including a suction conduit entering said header for removing gaseous refrigerant and lubricant therefrom, and means including an open-end elongated substantially cylindrical bailie arranged horizontally within said header and extending throughout its length partially below the level of liquid refrigerant in said header for separating lubricant from the liquid refrigerant within said evaporator, means including said suction conduit for supporting said baflie in said header, said suction conduit communicating with said header within said baffle.

5. A flooded evaporator for refrigerating machines of the type employing a liquefiable refrigerant and a liquid lubricant separable by gravity and including a header for separating liquid and gaseous refrigerant, means including a suction conduit entering said header for removing gaseous refrigerant and lubricant therefrom, and means including an elongated vessel communi- 5 cating at one end with said conduit and open at the other end and having the interior thereof throughout its length partially below the level of and covered by the liquid refrigerant in said header for separating lubricant from the liquid refrigerant in said evaporator, said suction conduit communicating with said vessel adjacent the level of liquefied refrigerant therein.

6. A flooded evaporator for refrigerating machines of the type employing a liquefiable refrigerant and a liquid lubricant separable by gravity and including a header for separating liquid and gaseous refrigerant, means providing a plurality 'of depending refrigerant circulating passages communicating with said header below the level of liquid refrigerant therein, means for producing a circulation of liquid refrigerant in an upward direction through some of said passages and in a downward direction through others of said passages, means including a suction conduit entering said header for removing gaseous refrigerant and lubricant therefrom, and means including an elongated vessel closed at one end and open at the other end and communicating at said closed end with said conduit and having said open end-partially below the level of liquid refrigerant in said header for separating lubricant from the liquid refrigerant in said evaporator, said open end of said vessel being substantially direct- 1y above one of said passages wherein liquid refrigerant is directed downwardly from said header.

CARL H. STEENSTRUP. 

